In Papousek's Conditioning of Infants to Turn Their Heads to a Buzzer

In Papousek's conditioning of infants to turn their heads to a buzzer or a bell to receive milk, what were his findings?

A) The earlier the training began, the older the infants were before they mastered the task.
B) The later the training began, the older the infants were before they mastered the task.
C) The earlier that any training begins, the earlier the infants can master a task.
D) The time when training begins has little effect on infants' ability to master a task.